One's best friend is oneself.

一个人最好的朋友是自己。

A stranger could be one's best friend just as one's wife and daughter could be one's deadly enemies, Teacher Fei replied, and he suggested that they go out for tea or a quick drink.

陌生人能变成最好的朋友，而妻子女儿却会成为死敌，范老师回答说，然后他建议他们一起去喝茶或喝点小酒。